I do not think what you're doing is "wrong", as such. However, beware of false feelings, or "rebound" reaction.
At the moment, this figure from your past appears to offer everything your husband did not. Of course it's tempting; of course it's exciting!
But how well do you really know him? Are you the same people you were in your teens? Are you seeing him as he really is now, or through a rosy tint of nostalgia?
I know exactly the hope you are investing in this, as I am shortly to meet a childhood crush I last saw in primary school! It's not quite the same, as I have not recently left (or possibly still in) another relationship.
But I do understand how much hope it's tempting to place in someone known since childhood - when we were young and innocent, before all the cr*p happened. I am having to try very hard not to have unrealistic expectations of my friend. To realise he's going to be a real man, with weaknesses and failings - not some shining angel come to rescue me. Yes, I'd love him to be that, but it's not fair, is it? How can a mere mortal live up to it?
And I wonder if you're doing the same with your chap? Wanting, and hoping, that he should be eveything, and overlooking that he's a real person - like you, like your husband - and he's not going to wave a magic wand and make everything perfect!